1. Field of the Invention
The disclosure herein generally relate to a liquid droplet forming apparatus.
2. Description of the Related Art
Recently, in accordance with a development of stem cell technology, a technique has been developed in which an organization body is formed by discharging a plurality of cells by inkjet. As the type of inkjet apparatus, a piezoelectric pressure type using a piezoelectric element, a thermal type using a heater, an electrostatic type in which liquid is attracted by an electrostatic attraction or the like may be used. Among these, the piezoelectric pressure type is preferred to be used for forming a droplet of a cell suspension because damage due to heat or an electrical field is harder to be caused to cells by this type compared with other types.
Upon discharging a droplet including particulate matter represented by a cell, detecting how much the discharged liquid droplet includes particles is important. Therefore, various methods of detecting a number of particles included in the discharged liquid droplet have been proposed.
For example, regarding an inkjet apparatus that pressurizes a liquid chamber (cavity) by a piezoelectric element (actuator) to form a liquid droplet from a nozzle, a technique of detecting a number and a form of granular bodies included in a liquid between the cavity and the nozzle from a side is disclosed (See, for example, WO 2011/099287). Therefore, a particle in the discharged liquid droplet can be recognized.
Another example discloses a technique of observing a liquid droplet discharged from a dispensing element including an inkjet element or the like from a side, and identifying a state of the liquid droplet and a trajectory (See, for example, Japanese Patent No. 4013869).